This invention relates to image-enhancement through color photography.
There has been recognized in the field of imaging a need for the enhancement of the images provided by such objects as oscilloscopes, i.e., cathode ray tube displays which are used in many diagnostic and viewing techniques, including particularly medical diagnostic procedures. As an example, the fields of ophthalmology, obstetrics, and cardiology have greatly benefitted from ultrasonography. In this technology, typical equipment includes a transducer which produces bursts of ultrasonic energy which are directed into human tissue as a collimated or focused beam. This beam strikes a tissue or fluid interface of different density, resulting in sonic echos which are reflected back to the transducer, where those sonic echos are converted into electric impulses, which are then amplified and displayed on an oscilloscope or cathode ray tube. There may be displayed by the oscilloscope an echo anatomic outline of structure beneath the skin, and provide a cross-sectional display of, for example, the eye, a pregnant abdomen or an internal organ such as the heart.
The oscilloscope display is a gray continuous tone image, varying between black and white at different portions of the image. In the medical field, radiologists and other physicians are trained to analyze the displayed image to provide evaluations of normal and abnormal conditions.
It has been recognized that the human eye has relatively poor gray scale performance; that is, the eye cannot discriminate over as wide a range of intensity levels as is desirable in order to assist in the interpretation and understanding of such oscilloscope continuous tone images. Recognition of the foregoing fact has led to the development of color-coded images, which has been accomplished with complex electronic equipment in which a color is arbitrarily assigned to each small range of magnitude of the ultrasonic pulse echo. This is in some respects similar to the arbitrary assignment of a part of the gray scale to similar small ranges in the magnitude of the reflected echo pulse. Color-coding of oscilloscopes has some limitations, and one of the more successful uses of color in coding is with relatively simple images which have few details and only slowly varying intensities.
Not only is the image on an oscilloscope screen viewed and diagnosed, but similar images provided by X-rays, are also viewed and diagnosed. This occurs both in the medical field, and other fields, including inspection of structures for hidden flaws, etc.
It is sometimes necessary to provide a fixed record or an additional fixed record of an oscilloscope image. For example, where a radiologist reads a X-ray or a set of X-rays, the information which he obtains and his opinion relative to the subject has to be given to another physician. In some instances, duplicate X-rays are provided to the other physician, and in some instances this may require as many as fifteen to twenty separate X-ray films. Where radiomagnetic imaging is used, as many as fifty different sheets may be required to be duplicated. Duplication is necessary where the radiologists and the physician are not in close proximity, and the treating physician considers it necessary to see the film in order to be properly guided by the evaluation provided by the radiologist. The production of duplicate X-ray films is often unduly time-consuming where time may be of great significance, and is always an added cost.
It has been the practice of some physician to preserve a record of the image obtained of a patient through sonography, and this has usually been achieved by photographing the image on the oscilloscope. Since the image is in black and white, black and white film was used.